C-Reactive Protein (CRP), an inflammatory biomarker, is influenced by many factors including socioeconomic position, genetics and diet. The inverse association between diet and CRP is biologically feasible because micronutrients with antioxidative properties may enable the body to manage the balance between production and accumulation of reactive species that cause oxidative stress.
To determine the quality of the diet consumed by urban, low-income African American and White adults aged 30 to 64 years, and association of diet quality with CRP.
Data from a cross-sectional study were used to evaluate diet quality assessed by mean adequacy ratio (MAR). Two 24-hour recalls were collected by trained interviewers using the USDA automated multiple pass method.
The sample consisted of Healthy Aging in Neighborhoods of Diversity across the Life Span baseline study participants, 2004–2009, who completed both recalls (n=2017).
Main outcome measures
MAR equaled the average of the ratio of intakes to RDA for 15 vitamins and minerals. CRP levels were assessed by the nephelometric method utilizing latex particles coated with CRP monoclonal antibodies.
Statistical analysis performed
Linear ordinary least square regression and generalized linear models were performed to determine the association of MAR (independent variable) with CRP (dependent variable) while adjusting for potential confounders.
MAR scores ranged from 74.3 to 82.2. Intakes of magnesium and Vitamins A, C, and E were the most inadequate compared to Estimated Average Requirements. CRP levels were significantly associated with MAR, DXA-measured body fat, and hypertension. A 10% increase in MAR was associated to a 4% decrease in CRP.
The MAR was independently and significantly inversely associated with CRP, suggesting diet is associated with the regulation of inflammation. Interventions to assist people make better food choices may not only improve diet quality but also their health, possibly reducing risk for cardiovascular disease.